Expansion board apparatus and removing method

ABSTRACT

In part, and in addition to apparatus and methods presented, an expansion board to be connected/disconnected to/from its mother board easily is provided. A face of a CDC (Communication Daughter Card), which is an expansion board to be connected to the mother board of a computer system is covered by an insulating sheet. In the CDC, an edge of one end of this insulating sheet is extended so as to form a projection. A user can take this projection with fingers, thereby carrying and connecting/disconnecting the CDC to/from the mother board easily.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application of filed parent application Ser. No.10/154,115 filed with the United States Patent and Trademark Office onMay 23, 2002 now U.S. Pat. No. 6,735,092, the teachings of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an expansion board, expansion board forcommunication, insulating film for expansion board, computer system,expansion board removing method, and electronic circuit board, and moreparticular to apparatus and method for such to be employed with computersystems

2. Description of Related Art

In recent years, so-called PCs (personal computers) have come to beprovided with more and more diversified functions. For example, many ofthose PCs are provided with functions for communicating with externaljust by connecting such an expansion device as a modem board, a LANboard, etc. to them. Those expansion devices are classified into twotypes; built-in type and external type. The built-in type device isinstalled inside the subject PC while the external type device isconnected to the subject PC from outside. Users often select and installnecessary expansion devices by themselves according to theirrequirement. For a built-in type device, the user is required to exposethe PC by removing the case and connect the board type expansion deviceto the connector of the mother board inside the PC.

However, some expansion devices cannot be installed by users.Concretely, those devices are small expansion devices for lap-top PCs.Because portability is an very important item for lap-top PCs, thoseexpansion devices are limited in size. Consequently, parts are packed ata high density thereon, so that the lap-top PCs become complicated ininternal structure. In addition, expansion devices must beinstalled/removed very accurately and carefully. This is why usually thePC makers install those small expansion devices in lap-top PCs; noconsideration is given to the installation of those devices by usersfrom the beginning.

In spite of this, year after year there have increased users who want toexpand the capability of their lap-top PCs more freely and accordingly,those users come to desire to install those small expansion devices bythemselves. It would therefore be a significant advantage for thoseusers if they could install/remove those expansion devices that arecomparatively expensive small expansion devices and mother boards etc.by themselves.

SUMMARY OF THE INVENTION

Under such circumstances, it is an object of the present invention tosolve the above conventional technical problems and provide an expansionboard, which enables users to connect/disconnect expansion devicesto/from mother boards of those lap-top PCs.

In order to attain the above object, in one aspect, the expansion boardof the present invention, connected to the mother board of the subjectcomputer system, is intended to expand the functions of the computersystem. The expansion board of the present invention comprises a firstface facing the mother board; a second face that is the back of thefirst surface; and a projection formed by a flexible sheet extended fromthe second face so as to be separated therefrom. The user canconnect/disconnect the small expansion board to/from a predeterminedposition inside the subject PC smoothly by taking this protruded sheetwith fingers. The shape of the flexible sheet is not limited specially;it is just required for the user to be able to take it with fingers. Forexample, the flexible sheet may be a narrow strap-like one.

Furthermore, in another aspect, the expansion board of the presentinvention to be employed for computer systems includes two surfaces;face and back. On the back is provided a connector used to connect themother board of the subject computer system and on the face is provideda grip used to take the expansion board with fingers.

The present invention, in a further aspect, may also be considered as acommunication expansion board. In this case, the communication expansionboard comprises a board provided with a primary area used to connect anexternal network and a secondary area used to connect a portion insidethe subject computer, an insulating film used to cover at least theprimary area, and a projection provided with a fixed end fixed to theface of the insulating film and a free end formed so as to be separatedfrom the insulating film.

The projection may be formed by extending the insulating film. In such acase, the insulating film is wound on the communication expansion boardin the width direction and the projection is extended in thelongitudinal direction of the board so as to cross the width direction.The projection may also be formed by a dedicated sheet separately fromthe insulating film. In such a case, the fixed end of the projection maybe formed by connecting one end of the dedicated projection sheet to theinsulating film. The projection may also be formed by winding thededicated projection sheet on the communication expansion board, thenconnecting both ends of the sheet to each other.

The present invention in still a further aspect may also be consideredas an insulating film for the communication expansion board. Theinsulating film used for the communication expansion board includes acover portion used to cover the face of the communication expansionboard and a projection extended from the fixed end on the face of thecover portion to external and enabled to be taken with fingers.

Furthermore in another aspect, the present invention may be consideredas a computer system. The computer system comprises accepting means foraccepting an expansion board removably; processing means for processingdata of the expansion board connected to the accepting means; boardholding means located on the face of the expansion board and enabled tobe held by the user so as to connect/disconnect the board to/from theaccepting means. This board holding means is preferably configured sothat the user can remove the board from the accepting means easily.

The computer system of the present invention also includes a motherboard and an expansion board connected to the mother board. The motherboard includes processing means and an expansion board connector used toconnect the board and send/receive data to/from the processing means.The expansion board includes a mother board connector used to connectthe mother board and an extended sheet extended from the face of theexpansion board.

In the computer system, the communication channel used for thecommunication with an external network is extended from the processingdevice and connected to the expansion board connector. The communicationchannel may include one of a modem channel, a LAN channel, and awireless LAN channel.

Furthermore in another aspect, the present invention may also beconsidered as a method for disconnecting the expansion board from themother board connector. According to the method, the user takes grip ofthe expansion board with fingers and pulls it so as to disconnect andremove the board from the mother board connector connected to the backof the board.

Further, for another aspect, the present invention may also beconsidered as an electronic circuit board. The electronic circuit boardcomprises first and second main faces that face each other; a connectorlocated on the first main face and enabled to connect an externaldevice; and a flexible sheet located on the face of the electroniccircuit board. Part of the flexible sheet is connected to the electroniccircuit board and another part thereof is extended so as to be separatedfrom the second main face. When an electronic circuit is mounted on thiselectronic circuit board, at least part of the electronic circuit can becovered by the flexible sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

Other aspects, features, and advantages of the present invention willbecome more fully apparent from the following detailed description, theappended claims, and the accompanying drawings in which:

FIG. 1 is a hardware block diagram of a computer system in an embodimentof the present invention;

FIGS. 2A and 2B are an expanded view of a CDC; FIG. 2A is a top viewfrom the face and FIG. 2B is a top view from the back;

FIG. 3 is a perspective view of the CDC that is not covered by aninsulating film;

FIG. 4 is a top view of the insulating film;

FIG. 5 is an expanded cross sectional view of the CDC connected to itsmother board;

FIG. 6 is a perspective view of the CDC of which projection is taken byfingers;

FIG. 7 is a top view of the projection formed position;

FIG. 8 is a top view of the CDC in another embodiment;

FIG. 9 is a perspective view of the CDC in still another embodiment;and,

FIG. 10 is a perspective view of the CDC in still another embodiment.

DETAILED DESCRIPTION

The use of figure reference labels in the claims is intended to identifyone or more possible embodiments of the claimed subject matter in orderto facilitate the interpretation of the claims. Such labeling is not tobe construed as necessarily limiting the scope of those claims to theembodiments shown in the corresponding figures. The preferredembodiments of the present invention and its advantages are bestunderstood by referring to the drawings, like numerals being used forlike and corresponding parts of the various drawings

Hereunder, the preferred embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings.

FIG. 1 shows a hardware block diagram of a computer system (computerapparatus) 10 in a first embodiment of the present invention. Thecomputer apparatus provided with this computer system 10 is configuredas a lap-top PC (Personal Computer) conforming, for example, to the OADG(Open Architecture Developer's Group) specifications and employs apredetermined OS (Operating System).

The computer system 10 shown in FIG. 1 is composed of a CPU (CentralProcessing Unit) 11 mounted on the mother board; a CPU bridge 15; an I/Obridge 21; a main memory 16; a PCI (Peripheral Component Interconnect)bus 20 used to connect various components; an ISA (Industry StandardArchitecture) bus 40; and an FSB (Front Side Bus) 12. The mother boardis provided with connectors and slots used to connect such expansionboards as a PC card 24; a mini-PCI device 60; a daughter card 70provided with functions for communications with external (hereinafter,to be described as the Communication Daughter Card (CDC)), etc., therebythe computer system 10 comes to have various additional functions.Hereunder, the configuration of the computer system 10 will be describedconcretely.

In the computer system 10 shown in FIG. 1, the CPU 11 mounted on themother board functions as the brain of the whole computer system 10 andexecutes various programs under the control of the OS. The CPU 11 isconnected to each component of the computer system 10 via three steps ofbusses as the system bus FSB 12, the PCI bus 20 used for fast I/Odevices, and the ISA bus 40 used for slow I/O devices. The CPU 11 storesprogram codes and data in a cache memory so as to process them fast. Inrecent years, an SRAM of about 128 KB is often provided in the CPU 11 asa primary cache. In addition, for a secondary cache 14, about 512K to 2MB is spared in the CPU 11 and used via a dedicated bus BSB (Back SideBus) 13. The BSB 13 may be omitted and the secondary cache 14 may beconnected to the FSB 12.

The FSB 12 and the PCI bus 20 are connected to each other via a CPUbridge (host-PCI bridge) 15 referred to as a memory/PCI chip. This CPUbridge 15 is configured so as to have memory controller functions forcontrolling the accesses to the main memory 16, a data buffer forabsorbing the data transfer speed difference to generate between the FSB12 and the PCI bus 20, as well as others.

The main memory 16 is used as an area for reading programs to beexecuted by the CPU 11 or as an area for writing data processed by thoseprograms. For example, the main memory 16 is configured by a pluralityof DRAM chips and it can be expanded as needed. The programs to beexecuted by the CPU 11 include various hardware drivers used to operatethe OS, as well as various peripheral devices, application programsdedicated to specific business works, and such firmware programs as theBIOS (Basic Input/Output System) stored in a flash ROM 44 to bedescribed later, etc.

The video subsystem 17 is used to execute video-related functions. Thevideo subsystem, 17 includes a video controller. This video controllerprocesses drawing instructions received from the CPU 11 and writesprocessed drawing information in a video memory and reads the drawinginformation from the video memory so as to output the information ontothe liquid crystal display (LCD) 18 as drawing data.

The PCI bus 20 enables data to be transferred comparatively fast. ThePCI bus 20 is standardized so that the data bus width is set to 32/64bits, the maximum operation frequency is set to 33/66 MHz, and themaximum data transfer speed is set to 132 MB/sec/528 MB/secrespectively. The I/O bridge (core bridge) 21, the card bus controller22, the audio subsystem 25, the docking station interface (Dock I/F) 26,and the mini-PCI connector (expansion board connector) 27 are connectedto this PCI bus 20 respectively.

The card bus controller 22 is used exclusively to connect the bus signalof the PCI bus 20 directly to the interface connector (card bus) of thecard bus slot 23. The PC card 24 can be connected to this card bus slot23. This PC card 24 is a kind of a device for expanding the capabilityof the computer system 10. The PC card 24 enables a device to beconnected to the dedicated card bus slot 23 from outside withoutexposing the computer system 10.

The docking station interface (Dock I/F) 26 is a hardware component usedto connect a docking station (not shown), which is a capabilityexpansion device of the computer system 10. When a lap-top PC is set atthe docking station, various hardware components connected to theinternal bus of the docking station can be connected to the PCI bus 20via the docking station interface 26.

The mini-PCI device 60 is connected to the mini-PCI connector 27. Themini-PCI device 60 is an expandable capability expansion card (board)conforming to the mini-PCI specifications. The “mini-PCI” means a mobilePCI standard; it is described as a supplement to the PCI Rev. 2.2specification. Functionally, the mini-PCI is equivalent to the fullspecification PCI. In addition, the mini-PCI connector 27 connects an AC'97 (Audio CODEC '97) link extended from the I/O bridge. The AC '97 linkis one of the specifications of sound devices and modem devices for thePCI bus. Usually, the AC '97 link has two channels. One of the twochannels is assigned to a sound device and the other is assigned to amodem device.

The I/O bridge 21 is provided with a bridging function for the bridgingbetween the PCI bus 20 and the ISA bus 40. The I/O bridge 21 is alsoprovided with the DMA controller function, the programmable interruptioncontroller (PIC) function, the programmable interval timer (PIT)function, the IDE (Integrated Device Electronics) interface function,the USB (Universal Serial Bus) function, and the SMB (System ManagementBus) interface function. The I/O bridge 21 also incorporates a real timeclock (RTC) in itself.

The DMA controller function enables data transfer between suchperipheral devices as an FDD, etc. and the main memory 16 not via theCPU 11. The PIC function enables a predetermined program (interruptionhandler) to be executed in response to an interruption request (IRQ)from each of the peripheral devices. The PIT function generates timersignals at predetermined cycles. Each interface realized by the IDEinterface function is connected to an IDE hard disk drive (HDD) 31, aswell as a CD-ROM drive 32 via an ATAPI (AT Attachment Packet Interface).Instead of this CD-ROM drive 32, another type IDE device such as a DVD(Digital Versatile Disk) drive may be connected to the interface. Suchexternal storage devices as the HDD 31, the CD-ROM drive 32, etc. arehoused in a place in the subject lap-top PC. The place is usuallyreferred to as a “media bay” or “device bay”. Those external storagedevices attached to the PC as standard might possibly be replaceablewith such other devices as an FDD, a battery pack or attachedexclusively.

The I/O bridge 21 is also provided with a USB port. The USB port isconnected to a USB connector 30 located, for example, on a wall of thelap-top PC body. In addition, an EEPROM 33 is connected to this I/Obridge 21 via the SM bus. This EEPROM 33 is a non-volatile memory usedto hold information such as a user-registered password, a supervisorpassword, the product serial number, etc. The data in the EEPROM 33 canthus be rewritten electrically. The I/O bridge 21 is also connected to apower supply circuit 50. The power supply circuit 50 is provided with anAC adapter 51; a battery changing circuit 54 used to charge the battery(second battery) (the main battery 52 or second battery 53) and changethe power supply path from the AC adapter 51/each battery; a DC/DCconverter 55 used to generate such DC constant voltages as 5V, 3.3V,etc. used for the computer system 10.

The I/O bridge 21 is also connected to a CDC connector 28 used toconnect a CDC. This CDC connector 28 is connected to a CDC (expansionboard, communication expansion board) 70. The CDC 70 is a capabilityexpansion daughter board dedicated for communications with external. Inthis embodiment, the CDC 70 is used as a LAN board conforming to theEthernet standard (hereinafter, to be described as a LAN CDC providedwith the LAN function). Signals are exchanged between the CDC connector28 and the I/O bridge 21 in accordance with the Ethernet interfacestandard. Concretely, the LAN interface converts analog signals receivedfrom the CDC 70 to digital signals through the PHY (Physical Layer) andthe digital signals are converted and processed by a MAC (Media AccessController) in accordance with the Ethernet protocol. The CDC 70 issmaller than the mini-PCI device 60 in size. For example, the CDC 70 hasan area of about 1/2.5 of the mini-PCI device 60.

In addition to the LAN interface, AC '97 link and USB (Universal SerialBus) interfaces are provided between the I/O bridge 21 and the CDCconnector 28. Consequently, in addition to the Ethernet standard LANboard, the CDC connector 28 can connect a CDC 70 provided with the modemboard function conforming to the AC '97 link specifications(hereinafter, to be described as a modem CDC) or such a CDC 70 as a USB(Universal Serial Bus) standard wireless LAN board, etc. (hereinafter,to be described as a LAN CDC).

The ISA bus 40 is slower than the PCI bus 20 in data transfer rate (forexample, bus width: 16 bits, maximum data transfer rate: 4 MB/sec). ThisISA bus 40 is connected to the embedded controller 41 connected to thegate array logic 42; the CMOS 43; the flash ROM 44; and the super I/Ocontroller 45 respectively. This ISA bus 40 can also be connected tosuch peripheral devices as a keyboard/mouse controller, which arecomparatively slow in operation. The super I/O controller 45 isconnected to the I/O port 46 and used to drive an FDD and control theinput/output of parallel data (PIO) via a parallel port and theinput/output of serial data (SIO) via a serial port. The embeddedcontroller 41 controls a keyboard (not shown) and some of the powermanagement functions.

Next, for a particular aspect, the configuration of the CDC 70 isdescribed.

FIG. 2 is an expanded view of the CDC 70 shown in FIG. 1. FIG. 2(a) is atop view from the face (second face) and FIG. 2(b) is a top view fromthe back (first face). FIG. 3 is a perspective view of the CDC 70 thatis not covered by the insulating film. FIG. 4 is another top view of theCDC 70 for denoting the shape of the insulating film. FIG. 5 is anexpanded cross sectional view of the CDC 70 for denoting how the CDC 70is connected to the mother board 100.

The CDC 70 is used for a LAN and composed of a board 80 and aninsulating film 90 that covers the face of the board 80 as shown in FIG.2(a). The CDC 70 has two surfaces; the face 80 s and the back (on whichan IC is mounted) 80 t that are faced each other. The approximate sizeof the CDC 70 is 45 mm (x direction: length) 28 mm (y direction: width)for example. As shown in FIGS. 3 and 5, the board 80 is composed of aconnector part 81 used to connect the CDC connector 28 on the motherboard 100; holes 85 a and 85 b used to fix the board 80 onto the motherboard 100 with screws; and an I/O connector part 82 used to connect amodular connector RJ-45 used to connect an external network. Those itemsof the CDC 70 are all located on the back 80 t. In FIG. 3, the detaileddescription of the circuits on the back 80 t of the board 80 is omitted.The connector part 81 of this CDC 70 is connected to the CDC connector28 on the mother board 100 while the circuit-mounted side 100 t of themother board 100 faces the back 80 t of the CDC 70 as shown in FIG. 5.

In the CDC 70, the primary circuit 88 in which the I/O connector part 82of the board 80 exists might receive a high voltage caused by lightningfrom an external network connected thereto via the modular connectorRJ-45 while the modular connector RJ-45 is connected to the I/Oconnector part 82. In order to avoid such a trouble, therefore, theprimary area 88 of the board 80 may be covered by the insulating film 90as shown in FIG. 2. The insulating film 90 is made of, for example, sucha flexible sheet as polypropylene sheet or the like. The insulatingsheet is preferably within about 0.05 to about 0.1 mm in thickness so asnot to increase the total thickness of the CDC 70 body.

In order to cover the board 80 by the insulating film 90 as shown inFIGS. 2A and 2B, for example, the insulating film 90 cut into a shape asshown in FIG. 4 is wound on the board 80 so that both x and y directionsare aligned at the primary area 88 of the board 80. The length of theinsulating film 90 is enough to go round the board 80 once in the ydirection and cover the primary circuit 88 in the x direction. Then, theinsulating film 90 is wound on the board 80 so that the rear edge part90 b of the insulating film 90 is almost aligned to the rear edge part80 b of the board 80 and the position of the hole 91 formed in theinsulating film 90 is aligned to the position of the hole 85 b of theboard 80. After this, the side edge parts 90 d and 90 c of theinsulating film 90 wound on the board 80 are put on top of one anotherand stuck with an adhesive. As a result, the primary area 88 is coveredand the secondary area is exposed in the CDC 70 as shown in FIG. 2B. Inthe secondary area is provided a connector part 81 used to connect theCDC connector 28 located on the mother board 100.

At this time, the insulating film 90 has a projection 95 protrudedoutside the front edge part 90 a in the x direction. In the CDC 70, thisprojection 95 is located on the face 80 s of the board 80 as shown inFIG. 2A. The user can take this projection 95 with fingers as shown inFIG. 6 so as to connect/disconnect the CDC 70 to the CDC connector 27 ofthe mother board 100 and carry the CDC 70 with him/her.

Hereinafter, the shape of the projection 95 is further described. Thedimensions of the projection 95 are, for example, 12 mm (95 w (width ofthe fixed end))×9 mm (95 d (length from the fixed end to the free end).When the insulating film 90 is wound on the board 80, the distance dbetween the tip of the projection 95 and the front end of the board 80is 1 mm. To make it easier to take the projection with fingers, thewidth 95 w of the projection 95 is preferably 7 mm or over, furtherpreferably be 10 mm or over. On the other hand, the length 95 d of theprojection 95 is preferably 7 mm or over so as to make it easier to takethe portion with fingers. While the upper limits of both width 95 w andlength 95 d are not limited specially, the width 95 w and the length 95d is preferably 30 mm or less and 35 mm or less respectively so that theprojection 95 is not become an obstacle when the CDC 70 is installed ina computer system 10.

The projection 95 shaped as described above is positioned so as to makeit easier to apply a force to the connector part 81 on the back 80 t, sothat the CDC 70 connected to the CDC connector 28 of the mother board100 as shown in FIG. 5 is disconnected easily from the mother board 100upward by taking the projection 95 of the CDC 70 with fingers as shownin FIG. 6. Concretely, the point of the force should preferably comes tothe center of the connector part 81 when the projection 95 is pulled up.

In this embodiment, the vertical center line 96 n that divides theprojection 95 into two parts in the y direction is aligned to thevertical center line 81 n that divides the connector part 81 into twoparts in the y direction. The distance between the horizontal centerline 81 m that divides the connector part 81 into two parts in the xdirection and the base end 96 of the projection 95 is set to about 5 mm.Because the base end 96 of the projection 95 is positioned around theconnector part 81, it is easy to disconnect the CDC 70 from the CDCconnector 27 of the mother board 100.

Furthermore, to make it easier to disconnect the CDC 70 from the CDCconnector 27 of the mother board 100, the base end center 96 c thatdivides the base end 96 of the projection 95 into two parts in the ydirection is preferably positioned in an installation area 87 shown inFIG. 7. The installation area 87 has a predetermined distance in the yand x directions from the center 81 c of the connector, which is a nodeof the vertical center line 81 n and the horizontal center line 81 m ofthe connector part 81. The predetermined distance on the face 80 s ispreferably within 10 mm from a position corresponding to the connectorcenter 81 c. Furthermore, each of the distances 87 a and 87 b in the ydirection is preferably 5 mm or under. The distance 87 d between theconnector center 81 c and the front end 80 f of the board 80 in the xdirection is preferably 4 mm or under (the distance between theconnector center 81 c and the front end 80 f of the board 80) and thedistance 87 c between the connector center 81 c and the rear end 80 e ofthe board 80 in the x direction is preferably 10 mm or under.

In the case of the insulating film 90, corners 94 a and 94 b that areboundaries between the front edge part 90 a and the projection 95thereof are curved. Because the corners 94 a and 94 b are curved suchway, when an attempt is made to disconnect the CDC 70 from the motherboard 100 by taking the projection 95 with fingers as shown in FIG. 6while the CDC 70 is connected to the CDC connector 28, a force appliedto the corners 94 a and 94 b of the insulating film 90 is notconcentrated at a point so much. This is why the endurance of bothcorners 94 a and 94 b of the insulating film 90 is improved.Consequently, when the projection 95 is pulled with fingers, theinsulating film 90 is prevented from being lengthened and cut off at thecorner 94 a/94 b. The curvature R of the curved corners 94 a and 94 b ispreferably 5 to 8 mm or so.

The shape of the corners 94 a and 94 b may be changed. For example, justlike the corners 94 c and 94 d of the CDC 70A shown in FIG. 8, each ofthe corners 94 a and 94 b may be formed obliquely towards the projection95 a from the front edge 90 a of the insulating film 90A. The shape mayalso be right-angled. Such the insulating film 90A may be made of asheet strong enough so as not to be cut off when the CDC 70A connectedto the CDC connector 28 is pulled off by taking the projection 95 a withfingers.

The connector part 81 of the CDC 70 is connected to the CDC connectorpart 28 of the mother board 100 such way. On the other hand, theconnector part of a flexible cable (not shown) is connected to the I/Oconnector part 82 of the CDC 70. The other end of the flexible cable isconnected to the modular connector RJ-45 so as to be connected to anexternal network.

When the computer system 10 is powered by the user in this state, an IDsignal is output from the mother board connector part 81 of the CDC 70via an output pin of the GPIO (General Purpose Input/Output) pins to aninput pin of the I/O bridge 21. The ID signal communicates the mainmemory 16 about that the CDC 70 is a LAN board. The GPIO pins are usedto input/output general signals and the GPIO-pin state can be changedfreely with use of a software program (CDC driver, etc.). The GPIO isused for communications with other chips. In this embodiment, a specifictype CDC is assigned to each of the GPIO pins. Consequently, an IDsignal issued when the CDC 70 is connected turns off a predetermined pinassigned to the LAN board ID signal beforehand at the input side of theGPIO of the I/O bridge 21. Then, the mother board (host) 100 outputsinformation that the CDC 70 connected to the CDC connector 28 isidentified as a LAN board to the main memory 16 via the I/O bridge 21.

As a result, the computer system 10 recognizes the CDC 70 as a devicethat functions as a LAN board, thereby executing processingsappropriately to the CDC 70 used as a LAN board.

As described above, the CDC 70 connected to the mother board 100 asshown in FIG. 5 enables the computer system 10 to make communicationsvia the LAN (CDC 70). In this case, because the CDC 70 has theprojection 95 formed with the insulating film 90, the user can adjustthe position of the CDC 70 to the CDC connector 27 easily by taking theprojection 95 with fingers, thereby the user can connect the CDC 70 tothe mother board 100 easily. When disconnecting the CDC 70 from the CDCconnector 27 of the mother board 100, the user can also do the workeasily by pulling the projection 95. Consequently, the use of the CDC 70will make it easier to expand the functions of the computer system 10and replace the functions of the computer system 10 with others easily.

Furthermore, because the projection 95 is formed by extending theinsulating film 90 in the above embodiment, the manufacturing cost canbe reduced more than that of any of the conventional insulating filmsthat are not provided with any projection. In addition, such theprojection 95 can be formed easily in the above embodiment.

FIG. 9 is a perspective view of another CDC provided with another shapedprojection in another embodiment of the present invention.

In the CDC 70B shown in FIG. 9, a projection film 98 is wound outsidethe insulating film 90B that covers the board 80. The insulating film90B is not provided with the projection 95, which is formed at theinsulating film 90 in the CDC 70 shown in FIG. 2(a). Around the frontedge 90 a of this insulating film 90B is wound the projection film 98.Both films 90B and 98 are stuck at mutual contact portions by anadhesive so as to form a projection 98 t. In this case, both films 98and 90B may be stuck all over or partially at those mutual contactportions. The projection 98 t is made of the same insulating sheetmaterial as that of the insulating film 90B. They may also be made ofdifferent materials.

The projection 98 t, because it is protruded outside from the back 80 tof the board 80, is easy for the user to take with fingers. The height98 d of the projection formed on the face of the insulating film 90B isabout 8 mm and the width 98 w of the insulating film 90B is about 14 mm.Just like the CDC 70, the base end 98 b of the projection 98 t ispreferably positioned around a portion corresponding to the center ofthe connector part 81 (not shown in FIG. 9) formed on the back 80 t evenfor this CDC 70B.

As described above, the projection 98 t may also be formed with amaterial different from that of the insulating film 90B for insulatingthe board 80. Such way, the insulating film enables the projection 98 tto be shaped and positioned freely when the projection 98 t is formedwith a non-continuous material. Consequently, the projection 98 t can bepositioned so as to make it easier for the user to take and easier for adisconnecting force to work on the connector part 81. This is why theuser can disconnect the CDC 70B from the CDC connector 27 of the motherboard 100.

While the CDC 70 has been described as a LAN CDC in the aboveembodiment, the insulating film 90 may also apply to a modem CDCemployed as the CDC 70. While the insulating film 90 is wound on theboard 80 just once in the LAN CDC 70, it may be wound twice. Especially,when the CDC 70 is used as a modem CDC, the insulating film 90 should bewound more than twice so as to assure the insulation.

FIG. 10 is a perspective view of still another CDC in still anotherembodiment of the present invention. The CDC is provided with aprojection whose shape differs from those in the above embodiments.

The CDC 70C shown in FIG. 10 is a wireless LAN CDC. In this case, unlikethe LAN CDC and the modem CDC that must be insulated, there is no needto insulate the CDC. The surface of the wireless LAN CDC is thus coveredby no insulating film. And, a projection 95 c is formed with a fixedtape 99 on the board 80 as shown in FIG. 10. At this time, the fixedtape 99 is preferably positioned on the board 80 where no suchcomponents as circuits are placed. And, because the fixed tape 99requires only a very small area, the fixed tape 99 is preferably such astrong double-sided adhesive tape or the like. On the other hand, thesheet that forms the projection 95 c is preferably a low stiffness onedifficult to be cut off at the base end 96. Preferably, the sheet thatforms the projection 95 c should be a flexible sheet made of the samematerial as that of, for example, the insulating film 90 used for theCDC 70.

Because the base end 96 is fixed to the surface of the board even at theCDC 70C that requires no insulating film in this embodiment as describedabove, the projection 95 c can be formed easily. The user can thus takethe projection 95 c of the CDC 70C so as to connect/disconnect the CDC70C to/from the CDC connector 27 of the mother board 100 easily.

It is also possible to form the projection at the above-describedwireless LAN CDC by covering both face and back of the CDC just like theLAN CDC.

While the computer system 10 in this embodiment is provided with onlyone CDC connector 27 that connects the CDC 70/70A/70B/70C, the presentinvention can apply to a computer system provided with a plurality ofCDC connectors used to connect a plurality of CDCs.

While a description has been made only for the CDC in this embodiment,the present invention can apply to such expansion boards as the mini-PCIdevice, the MDC, etc. The functions of the expansion board of thepresent invention, to be added to the computer system 10, are notlimited only to functions of communications with external; the functionsmay be those of video cards, memories, etc.

In addition to those described above, obviously many more modificationsand variations of the present invention are possible without departingfrom the spirit of the present invention.

1. A communication expansion board, comprising: a board including aprimary area used to connect an external network, and a secondary areaused to connect a portion inside a computer; an insulating film used tocover a selected portion of said primary area of said board; and aprojection including a fixed end fixed to the face of said insulatingfilm, and a free end separated from said insulating film, wherein saidprojection is formed by a sheet wound on said communication expansionboard, both ends of said sheet are connected to each other so as to formsaid projection.
 2. The communication expansion board of claim 1,wherein said projection is formed by extending said insulating film. 3.The communication expansion board of claim 2, wherein said insulatingfilm is wound on said communication expansion board in a widthdirection; and said projection is protruded in a longitudinal directionof said communication expansion board so as to cross said widthdirection.
 4. The communication expansion board of claim 1, wherein saidprojection is formed by a sheet; and said fixed end of said projectionis formed by connecting one end of said sheet to said insulating film.